The present invention relates to a grain wagon or cart of the type disclosed in U.S. Pat. No. 5,340,265, U.S. Pat. No. 6,296,435 and U.S. Pat. No. 7,134,830 which issued to the assignee of the present invention and which are commonly pulled by a tow tractor for transporting grain from a harvesting combine in a field to an open top semi-trailer which transports the grain over the road to a grain elevator for storage. In such a grain cart, the power driven single auger grain unloading conveyor includes an inclined lower auger conveyor section which extends adjacent an inclined front left corner portion of the container and an upper auger conveyor section which projects upwardly, laterally outwardly and forwardly from the container in a grain discharge position so that the discharging of the grain can be conveniently viewed by the operator or driver of the tow tractor. The upper auger conveyor section is pivoted by a fluid cylinder to a stored position adjacent the front wall of the container, as shown in the above-mentioned '281 patent and also in U.S. Pat. No. 5,655,872. This front folding upper auger conveyor section also enables the driver of the tow tractor to view all movements of the upper conveyor section between its stored position and its grain discharge position.
It has been found desirable to construct a grain cart with a single discharge auger conveyor and a bin or container having a larger grain capacity, for example, a capacity of over thirteen hundred bushels. It is also desirable to have the larger capacity container without using a dual auger system, such as disclosed in U.S. Pat. No. 4,846,621 and U.S. Pat. No. 6,776,569 and used in a grain cart manufactured and sold under the trademark “Brent”. The dual auger system involves significantly more construction, assembly and manufacturing costs and significantly more maintenance costs. Above-mentioned U.S. Pat. No. 7,134,830 discloses a larger capacity grain cart with a single discharge auger conveyor and wherein the grain container has the optimum width of approximately twelve feet so that the grain cart may be transported or delivered over the road on the bed of a truck or trailer without requiring an escort permit.
It is further desirable for the upper section of the single auger conveyor to project upwardly, laterally outwardly and forwardly of the container in the grain discharge position by an extended distance for the reasons mentioned above and in order for the grain cart to unload into a semi-trailer which may be positioned further away from the grain cart, for example, on a road bed or on the other side of a ditch or fence. One method of extending the upper portion of the auger conveyor is to provide the tubular auger housing with a telescopic outer housing extension operated by a fluid cylinder, for example, as disclosed in U.S. Pat. No. 6,497,546 which issued to the assignee of the present invention. However, such a housing extension adds to the cost of manufacturing and maintenance of the auger conveyor, and it is desirable to avoid the loss of grain from between the telescopic housing sections.